Video conferencing is increasingly employed to facilitate communication between parties at different locations. Current video conferencing technology allows video and audio information, captured at various video network endpoints, to be selectively shared among video conference participants. The benefits of video conferencing include not only enhanced audio and video communication, but also an elimination of the time and expense of travel. However, as the number of participants in the video conference increases, a number of difficulties may limit the efficiency of sharing the video conference information with all participants. Specifically, as the number of video conferencing endpoints involved within a specific video conference increases, the bandwidth necessary for transmitting the video conference is often prohibitive.
An MCU is a device commonly used to bridge video conferencing connections, and may more generally also be referred to as video conference bridge. The MCU may be connected to a Local Area Network (LAN), and provides the capability for three or more terminals and gateways to participate in a multipoint conference. An MCU has one port with a full range bandwidth and a codec (coder/decoder) for each participant providing video communication according to the H.264/MPEG-4 AVC standard and similar standards. MPEG is short for Moving Picture Experts Group and AVC is short for Advanced Video Coding. The H.264/MPEG-4 AVC standard is a standard for video compression.
In certain applications, video conference participants may be roughly divided into two groups: active participants and passive participants. Active participants may be categorized as those video conference participants who are actively speaking; on the other hand, passive participants may be categorized as those participants who are primarily viewing or watching the video conference. For example, a panel discussion may include several active participants who may or may not be located at different geographical locations. The panel discussion may also have an interested audience made up of multiple passive participants at various locations. In a traditional video conference setting, broadcasting this video conference to all participants would require the traditional broadcast of video conferencing to all locations. Accordingly, if the number of active and passive participants were in multiple different physical locations, this broadcast would require a significant amount of bandwidth and telecommunication resources. However, this is not an effective use of resources because the passive participants are not taking full advantage of the resources available.
In the case described above, too much redundant resources are used to keep the passive participants connected to the conference. One specific problem related to this is the fact that when one participant experiences packet loss, it will, according to the H.264/MPEG-4 AVC standard and other similar standards like SIP (Session Initiated Protocol) and H.323 (referred to as the Standard), require the MCU to create an I-frame (Intra frame) for all the participants connected to the MCU. This will appear as “blinking” effect to all the participants in the conference, i.e. the screen gets black for a moment followed by a picture starting with the new I-frame.
Therefore, there is a need for a broadband optimization and a way to prevent “blinking” when a passive participant in a video conference is exposed to packet loss.